1. Field of the Invention
The present invention relates to a hot and cold water mixing valve that mixes hot and cold water and discharges mixed water at a specific temperature, of the type in which mixed water of the desired temperature is automatically controlled and discharged by a control mechanism that is controlled by a bias spring and thermo-element or SMA spring incorporated within the body, and the setting temperature is changed and adjusted by a temperature adjustment handle provided at one end of the body, and more particularly to an improved temperature adjustment handle autorotation prevention device in which the temperature adjustment handle provided at one end of the body for changing and adjusting the setting temperature is prevented by the reaction of a spring from autorotation that would disturb the setting temperature.
2. Description of the Related Art
As shown in FIG. 1, an automatic hot and cold water mixing valve in which the setting temperature of the discharged water is changed and adjusted by rotation of a temperature adjustment handle provided at one end of the body normally includes a body A formed in a cylindrical shape, including a case 1 formed in a cylindrical shape open at one end (the right end in the figure), and a cylindrical shaped valve seat 2 connected to the open end of the case 1, provided with a hot water inlet 3 and a cold water inlet 4 in the cylindrical wall, a cylindrical shaped control valve body 5 that controls the rate of flow of hot water flowing in from a hot water inlet 3 and the cold water flowing in from a cold water inlet 4 is inserted within the body A so that the control valve body 5 can move in the axial direction (the horizontal direction in FIG. 1), a first end of the control valve body 5 (the left hand side on the drawing) is in contact with and coupled to a first end of a bias spring 6, and a second end of the bias spring 6 is supported by a shaft 8 supported by an adjusting screw 7 that is capable of moving in the axial direction but is restricted from rotating by spline grooves in the body A. A first end (left hand side in the drawing) of a temperature sensitive spring 10 positioned within a mixing chamber 9 formed in an internal cavity of the cylindrical shaped valve seat 2 forming one end of the body A is in contact and coupled with a second end of the control valve body 5, a second end of the temperature sensitive spring 10 is supported by a spring seat 11 formed integrally and continuously with the internal cavity of the cylindrical shaped valve seat 2, and in this way the control valve body 5 is maintained in the position of equilibrium between the two springs, the bias spring 6 and the temperature sensitive spring 10. The rate of inflow of hot water and the rate of inflow of cold water are controlled to their respective rates in accordance with the intervals set between a hot water valve a at the first end of the control valve body 5 and a hot water valve seat b in confrontation thereto, and the interval between a cold water valve c at the second end of the control valve body 5 and a cold water valve seat d in confrontation thereto, when the control valve body 5 is set in the balanced stable position, and the hot and cold water is transmitted to the mixing chamber 9 in the mixing proportions in this way, and mixed water at a fixed temperature is discharged from a mixed water outlet 12 formed in an end of the cylindrical shaped valve seat 2.
In this way, when the inflow of cold water reduces due to a reduction in water pressure, the temperature of the mixed water in the mixing chamber 9 rises accordingly, the load in the temperature sensitive spring 10 positioned in the mixing chamber 9 increases due to the temperature sensitivity effect, and pushes against and compresses the bias spring 6, the control valve body 5 is pushed and the gap between the hot water valve a and the hot water valve seat b narrows, and the inflow of hot water reduces, also when the inflow of cold water increases due to an increase in water pressure or similar, the temperature of the mixed water reduces, the load in the temperature sensitive spring 10 reduces due to the temperature sensitivity effect, the bias spring 6 extends, the gap between the cold water valve c and the cold water valve seat d narrows, the inflow of cold water reduces, and in this way the temperature of the mixed water that had reduced rises. The control valve body 5 becomes stabilized at a position where the mixing ratio of hot and cold water and the temperature of the mixed water are balanced, so the configuration automatically controls the temperature of the mixed water to a constant setting temperature.
The setting temperature set by the position of equilibrium between the two springs is changed and adjusted to the desired temperature by the rotational operation of a temperature adjustment handle B provided on a first end of the body A, which rotates an adjusting screw receiver 13 incorporated in a cavity at the first end of the body A, which moves the adjusting screw 7 coupled to the adjusting screw receiver 13 in the axial direction (the horizontal direction in the drawing), which moves the shaft 8 supported by the adjusting screw 7 in the axial direction, which changes the position of support of the second end of the bias spring 6, which alters the position of equilibrium of the two springs.
However, automatic hot and cold water mixing valves configured in this way have the problem that, for example, when high temperature mixed water is required the temperature adjustment handle B is rotated in the high temperature direction to the position of the scale of the required temperature, the temperature sensitive spring 10 and the bias spring 6 which are in balance are compressed, and the reaction of the resultant force in the springs act on the adjusting spring 7, which acts on the temperature adjustment handle B, and the result is autorotation of the temperature adjustment handle B towards the low temperature side, which affects the setting temperature.
On the other hand, when low temperature mixed water is required, there is the problem that the temperature adjustment handle B is rotated in the low temperature direction, at this time a pull up spring provided to maintain contact between the shaft 8 and the adjusting screw 7 contracts, and autorotation of the temperature adjustment handle B in the opposite direction occurs to the high temperature side due to the reaction of the pull up spring, which affects the temperature setting.
Therefore in this automatic hot and cold water mixing valve it is necessary to ensure that when rotating the temperature adjustment handle to set the temperature of the mixed water, autorotation of the rotated temperature adjustment handle does not occur due to the reaction of the springs.
FIG. 2 shows means that has been used to prevent autorotation in the temperature adjustment handle B. This is technology disclosed in Japanese Patent Application Laid-open No. 58-040060, as shown in FIG. 2, in a thermo-element mixing valve, an actuation spring 50 acts on a control valve body 5 via a temperature detecting element 51 whose stem moves in and out as a result of temperature variations, an actuating shaft 52 that supports a bias spring 6 is screwed to a spindle shaft 53 coupled to a temperature adjustment handle B, as a result of the operation of rotating the temperature adjustment handle B hot water that flows in from a hot water inlet past a hot water valve seat a and cold water that flows in from a cold water inlet past a cold water valve seat c are mixed, and the mixed water is discharged, the means being when the temperature adjustment handle B is rotated, a reaction force from the bias spring 6 acts on the actuation shaft 52, and a reaction force in the opposite direction from a coil spring w also acts on the actuation shaft 52, so that the reaction forces cancel, and autorotation of the temperature adjustment handle B does not occur.
Next, as shown in FIG. 3, in an automatic hot and cold water mixing valve in which a temperature sensitive spring (SMA spring) 10 and a bias spring 6 are coupled to a control valve body 5, a shaft 8 that supports one end of the bias spring 6 is inserted so that the shaft 8 can freely slide in an adjusting screw 7, the shaft 8 is coupled to the adjusting screw 7 by an engaging collar 80 provided on the shaft 8, and a pull up spring y is provided on the tip of the projection of the part of shaft 8 that penetrates the adjusting screw 7, the means being when a temperature adjustment dial B is rotated to the low temperature side, an adjusting screw receiver 13 coupled to the temperature adjustment dial B rotates, and when the adjusting screw 7 screwed to the adjusting screw receiver 13 is raised up, in order to cancel the reverse reaction of the pull up spring y that is shortened by this movement, an autorotation prevention spring v is provided as a coil spring coaxial with the pull up spring y between the adjusting screw receiver 13 and the adjusting screw 7, that is compressed and acts to press the adjusting screw 7 downwards when the adjusting screw 7 rises up.
Therefore in automatic hot and cold water mixing valves in which a temperature adjustment handle is rotated to set the temperature of the mixed water to the desired temperature, when rotation of the temperature adjustment handle to set the temperature is completed, autorotation of the temperature adjustment handle occurs which rotates the temperature adjustment handle which disturbs the temperature setting, so it is necessary to prevent this autorotation, and for this purpose a coil spring is included whose axial direction is the same as the direction of movement of a temperature sensitive actuator to cancel out the force that causes autorotation of the temperature adjustment handle, and this results in the problems that the length of the body in the axial direction is increased, and size reduction becomes difficult.